This invention relates generally to the conversion of amorphous or polycrystalline semiconductor materials to substantially single crystal semiconductor material by a process known as zone-melting-recrystallization (ZMR).
The development of silicon-on-insulator (SOI) technology has been complemented by the use of ZMR processing to produce single crystal silicon for solid state devices exhibiting reduced parasitic capacitance, simplified device isolation and design, and radiation hard circuits for space applications.
Present ZMR processes require a well controlled mechanical system to translate a hot zone created by a moving strip heater across the surface of a heated silicon wafer. This system is elaborate, expensive, and has a number of mechanical parts that could degrade in time. U.S. Pat. No. 4,371,421 entitled "Lateral Epitaxial Growth by Seeded Solidification" describes such a system.
A sample to be recrystallized is placed on a heater which raises the temperature of the sample close to its melting point. A strip heater positioned above the sample is then energized to induce melting of a zone on the sample directly beneath the strip heater element. The strip heater is then translated past the surface of the sample, causing the melting zone to move in unison with the heater to induce melting then solidification of the sample to achieve lateral epitaxial growth thereby transforming the sample into a single crystal material.